Telephone-transmitter



(No Model.)

J. H. IRWIN.

TELEPHONE TRANSMITTER.

Patented Dec. 27, 18-81.

INVENTOF?! UNITED STATES PATENT OFFICE.

JOHN H. IPAVIN, OF MORTON, PENNSYLVANIA. I

TELEPHONE-TRANSMITTER.

SPECIFICATION formingpart of Letters Patent No. 251,590, dated December 27, 1881.

Application filed February 16, 1881. (No model.)

To all whom "it may concern:

Be it known that I, JOHN H. IRWIN, a citizen of the United States, residing at Morton, in the county of Delaware and State of Pennsylvania, have invented certain new and useful Improvements in Telephone-Tiansmitters; and I do hereby declare thet'ollowingtobeat'ull,clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters orfignres of reference marked thereon, which form apart ofthis specification.

My invention relates toimprovemcntsin those forms of articulating telephones known as contact or battery transmitters, in which two or more contacts or electrodes in constant circuit with a battery are caused to varythe tension of the electric current flowing from said battery, when they are acted upon by soundwaves, in such a way that the current, carried through a proper receiving-instrument, will reproduce from said instrument articulate speech or sounds of the same characteristic nature as the original exciting sounds,which act upon the transmitter.

In instruments of this kind as heretofore constructed the electrodes are liable to get out of adjustment, the transmitted sounds are accompanied at the receiver by peculiarsputtering or hissing noises, and the sounds reproduced at the receiver are very much weaker than the original exciting sounds.

My invention is designed to improve the constancy of adjustment and action of this class of instruments to preserve the electrodes,when either or both are of metal, froth oxidation; to prevent the hissing or sputtering noises that accompany the received sounds; to produce an increase in the amplitude of electrical pulsa-- tions set up by the transmitter, and a consequent increased volume of sound in the receiver, and to add to the clearness of the articulation. These results I have found by experiment are all attendant in greater or less degree upon my invention.

My invention consists in immersing the contact points or electrodes of an articulating-telephone-battery transmitter in a liquid, (prefer- 5o ably one that is not readily decomposable by I have stated that the liquid in which the contacts are immersed is preferably a non-conductor and not readily decomposable by the electric current. This is not, however, absolutely necessary, and good results may be obtained, so far as concerns loudness of sound, by the use of water when the transmitter is used in the primary circuit of an induction-coil whose secondary is to line; but a liquid of this kind, owing to the decomposition and sudden liberation of its constituent gases, gives rise to the objectionable hissing and sputtering sounds before mentioned, and I therefore prefer, as before stated, to use-a liquid that is practically a non-conductor. I find in practice that the ordinary refined petroleum of commerce gives all the results mentioned in marked degree; but other hydrocarbon oils may be used in its place with as good, or nearly as good, results, and I have obtained excellent efi'r'cts also by the use of common machine-oil. It is, of course, desirable to select for this purpose Oils that are non-volatile, in order that the immersing-liquid may not require frequent renewal.

In carrying out my invention I simply build up around the resistance-contacts of the telephone a liquid-holding receptacle. Various forms of instruments may be used or devised for this purpose.

The drawings Figures 1 and 2 show, in vertical section, two forms that may be employed. In Fig. 1 is shown the electrodes delineated in Fig. 3 of the drawings of the patent granted to me October 22, 1878, No. 209,266. C is the upper electrode, preferably of platinum, suspended by a delicate coiled spring. The lower or carbon pencil, D, is inclosed in a cup carried to a sufficient height to readily hold the immersing-liquid.

In Fig. 2 another form of contact-transmitteris shown,in which D is a diaphragm or soundreceiving surface; E, acarbon button, secured in any suitable manner to said surface; F, a

spring attached to the diaphragm, and carrying at its lower end a platinum point or electrode resting in contact with the carbon, and G a cup for containing the liquid, also attached to the sound-receiving surface. 7

Fig. 3 is adiagram showing acontact-transmitter whose electrodes are immersed in a liquid used in the primary circuit of an inductioncoil, 1, whose secondary is to line. T represents the sound-receiving surface of the telephone, upon which is mounted a cup, a, containin ga carbon electrode whose surface is covered with a liquid. A weighted spring or reed,p, also attached to the sound-receiving surface, carries'a metallic electrode, 1", dipping into the liquid and resting upon the carbon button. M is a receiving-telephone, placed in the line-wire at the distant station.

A telephone-transmitter whose contacts are immersed in a liquid after the manner of my invention operates in the ordinary manner; but the improt ed results, so far as concerns -loudness and clearness of articulation, absence of hissing or sputtering noises, constancy of action, &c., are very marked.

In another application for patent filed by me on the 28th day of January, 1881, I have described and claimed an electrode for a telephone saturated or moistened with a non-conducting liquid, and I have stated in said application that I believed the sputtering or hissing sounds observable in the use ofcontact-transmitters to be due in large degree to the decomposition of the aqueous vapor or moisture present in the pores ofthe carbon. My presentinvention isan improvement upon the one therein described, and,while it will preventthe occurrence of the sputtering or hissing noises before referred to by excluding the aqueous vapor or moisture from the carbon and from the point of contact, has other and additional advantages in the particulars hereinbefore described.

What I claim as my invention is-- 1. In combination with the contact-electrodes of a battery-transmitter, an inclosing cup or chamber constructed to hold a liquid when the transmitter is in position for use.

2. A contact or battery transmitter, in combination with a non-conducting liquid in which the electrodes of said transmitter are immersed.

3. A contact or battery transmitter whose electrodes are immersed in a hydrocarbon liquid.

4. A telephone-transmitter whose electrodes are immersed in petroleum or mineral hydrocarbon.

5. A telephone-transmitter consisting of a platinum point or electrode, a carbon button or resistance-piece, and a liquid surrounding and immersing the electrodes at the point of contact.

6. In a telephone contact-transmitter, the combination of a platinum point or electrode, a carbon resistance piece or electrode, and a hydrocarbonliquid surrounding said electrodes at the point of contact.

7. In a telephone-transmitter, the combination of a platinum point or electrode, a resistance-piece of carbon, and'an inclosing cup or holder containing petroleum, substantially as described.

8. A telephone-transmitter in the primary circuit of an induction-coil whose secondary is to line, in combination with a liquid surrounding andimmersing the con tact-electrodes of said transmitter, substantially as described.

9. A telephone-transmitter whose electrodes are immersed in oil at their point of contact, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

J. H. IRWIN.

Witnesses:

A. M. PIERCE, F. W. HANAFORD. 

